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Retirement Plans (Fair Value Asset Allocation) (Details) - USD ($) $ in Millions | Sep. 30, 2019 | Sep. 30, 2018
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 351.6 | $ 343.5
Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 14.3 | 18.4
Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 337.3 | 325.1
Mid- Cap Growth Funds [Member] [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 9.8 | 10.1
Mid- Cap Growth Funds [Member] [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Mid- Cap Growth Funds [Member] [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 9.8 | 10.1
Equity Securities [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 66.4 | 72.8
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 6.9 | 11.8
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 59.5 | 61.0
Large Cap Growth Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | 30.6
Large Cap Growth Funds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | 0.0
Large Cap Growth Funds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets |  | 30.6
Large Cap Index Funds [Member] [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 29.8 |
Large Cap Index Funds [Member] [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 |
Large Cap Index Funds [Member] [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 29.8 |
Small Cap Growth Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 9.6 | 10.0
Small Cap Growth Funds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Small Cap Growth Funds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 9.6 | 10.0
Mutual Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 6.9 | 11.8
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 6.9 | 11.8
Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
International Stocks [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 10.3 | 10.3
International Stocks [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
International Stocks [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 10.3 | 10.3
Fixed Income Funds [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 277.8 | 264.1
Fixed Income Funds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 0.0 | 0.0
Fixed Income Funds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 277.8 | 264.1
Cash and Cash Equivalents [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 7.4 | 6.6
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | 7.4 | 6.6
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Fair value of plan assets | $ 0.0 | $ 0.0

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